This invention is directed to hygienic absorbent articles, such as diapers, adult incontinence articles, feminine protection articles and the like. More particularly, the invention relates to absorbent articles including a thermal cell actuator.
Absorbent articles are well known in the art. These articles typically have an absorbent core, which is held or positioned against the body of the wearer during use by a fastening system, such that bodily exudates are caught by the article. Typical absorbent articles include a topsheet facing the wearer which permits fluid exudates to pass through and a backsheet which prevents the exudates from escaping from the absorbent article.
Many advancements have been made in the art since the introduction of the disposable absorbent article. However, problems still exist relating to ease of application of the article to the wearer and isolation of bodily waste. Attempts have been made to isolate fecal waste by employing pockets, topsheets with receiving apertures, spacing elements, barrier cuffs, and other physical means. In some cases, such structures have the deficiency of inadequately maintaining coordination with the wearer""s body, especially the waste outlet points and/or the portions of the wearer""s body near the perimeter of the product. Attempts have also been made to improve the application of the article to the wearer by the use of adhesive tapes and mechanical fastening systems such as Velcro(copyright). However, the articles are still difficult to apply to mobile wearers using only two hands.
In an effort to overcome the deficiencies of the prior art, topical adhesives such as hydrocolloid, silicone, and hydrogel adhesives have been incorporated into disposable articles as a means of better positioning the article or maintaining body contact. However, the addition of such adhesives can have the negative effects of complication of removal of the product because they adhere aggressively to the wearer""s skin and/or other components of the disposable article. However, without supplemental sources of heating or cooling to activate or deactivate the thermally activatable or thermally deactivateable adhesive, the specific adhesive choice may be practically limited, for example to adhesives which are activatable at or near body temperature and deactivatable below or near body temperature.
In U.S. Pat. Nos. 5,649,914 and 5,797,892; a toilet training aid is disclosed which generates a heating or cooling effect in the presence of urine from the wearer within the article. The heating or cooling effect is intended to cause the wearer discomfort in an attempt to aid in the toilet training process. This heating or cooling effect performs no useful function upon the article itself. Instead, the toilet training aid acts upon the wearer to cause the wearer to take some action (i.e., remove the wet article and apply a new one). Further, the toilet training aid responds solely to conditions within the article itself, not to conditions between the article and the wearer. Further, the toilet training aid is only functioning for a short period of time and is not designed to provide a sustained reduction in relative humidity or temperature for typical wear times.
Also, absorbent articles tend to have elements which have the same or essentially the same properties upon application as during the wearing period. For example, while the tension in stretch panels changes once a stretch diaper is applied to a wearer, the modulus of the materials comprising the stretch panels remains essentially constant other than minor hysteresis loss. The lack of change in properties of materials or structures between application and wearing of the article can result in failure to optimize both the properties during application of the article and the properties during wearing. Compromises may result which minimize the overall effectiveness of the article or make application of the article more difficult. While heat shrinkable materials have been used in the process of constructing absorbent articles, such as to contract a portion such as a waistband thus changing its properties, such articles do not react to or change properties given a temperature change following the manufacturing process. Post-manufacturing changes in material properties may be attained by using heating or cooling element as disclosed in the present invention.
Therefore, it would be desirable to provide a thermal cell actuator which performs a useful function on an absorbent article, such as changing properties of at least a portion of the article or the altering the conditions between the article and the wearer. That is, it would be desirable for absorbent articles to include a xe2x80x9cthermal cell actuatorxe2x80x9d which actuates some useful function.
The present invention solves the deficiencies of the prior art by providing an absorbent article comprising: a topsheet, a backsheet joined with at least a portion of the topsheet, an absorbent core disposed between at least a portion of the topsheet and the backsheet; and a thermal cell actuator capable of adding or removing heat to or from at least a portion of the absorbent article to perform a useful function on the article. The thermal cell actuator can be activated by the wearer, caregiver, or environment conditions between the article and the wearer at the point in time the heat addition or removal is needed.